What does it mean when you have a "synchronized" transmission?

[MH8675309]

I drove a 15 speed when I hauled sugar beets and never used the clutch except to start. With a full load of beets you'd shift 4 times before you got through an intersection.

 

[Baby Grand]

I drove a 15 speed when I hauled sugar beets and never used the clutch except to start. With a full load of beets you'd shift 4 times before you got through an intersection.

Drove a Quadruplex straight job delivering lumber. Same deal. Shifting without clutching was much faster, especially when changing the compound shifter and the main shifter at the same time (twin stick). Saved a lot of momentum when climbing a hill from a full stop.